Conventionally, a vehicle has been put into practice in which an idle stop function which improves a fuel economy (consumption) and an exhaust performance by automatically stopping an engine when a predetermined stop condition is established in a situation in which the vehicle is stopped due to a traffic signal wait during a traveling of the vehicle. After the automatic stop of the engine, the engine is automatically re-started when a predetermined start condition is established and the vehicle is started. In addition, some of the vehicles in which the idle stop functions are equipped have a function which holds a brake force for the vehicle regardless of a brake pedal manipulated variable by a driver, during an automatic stop of the engine.
For example, in the vehicle described in a Patent Document 1, a brake force holding control in which the brake force of a brake device is held constant during the automatic stop of the engine is carried out. In this brake holding control, the brake force is held constant during a predetermined brake holding time from a start of a re-start after the automatic stop of the engine so as to prevent the vehicle from a reverse movement, from the start of the re-start of the engine to a generation of a driving force. Furthermore, a brake holding time duration in accordance with a depression quantity of an accelerator pedal within a constant time from a time at which the re-start of the engine is started is searched and the brake holding time duration is modified. Thus, as the depression quantity of the accelerator pedal becomes larger, the vehicle can speedily be started.
By the way, in case of the vehicle in which an automatic transmission is intervened between the engine and a driving wheel, engagements/releases of frictional engagement elements in the automatic transmission are ordinarily controlled by a hydraulic pressure. An oil pump to generate this hydraulic pressure is generally a mechanical (oil) pump driven by the engine. In some of the vehicles, an electrically driven (oil) pump is mounted in addition to the mechanical pump.
Since the mechanical pump is stopped when the engine is stopped, a supply of the hydraulic pressure to the frictional engagement elements is stopped during the automatic stop of the engine.
In other words, in case of the vehicle in which the electrically driven pump is not provided, the engagements of the frictional engagement elements are released due to the automatic stop of the engine. In case where the vehicle is started when the start condition is established, it is necessary to again engage the frictional engagement elements. Thus, a shock is generated in a proximity of a revolution synchronization during the engagement of the frictional engagement element(s) so that an unpleasant feeling is given to a vehicular occupant (especially a driver). In addition, in case where an operation of the accelerator pedal is carried out by the driver during the start of the vehicle, it is desirable to generate the driving force at an early stage.
In contrast, in the vehicle in which the electrically driven pump is equipped in addition to the mechanical pump, the hydraulic pressure can be continued to be supplied to the frictional engagement elements by the electrically driven pump even during the automatic stop of the engine and the frictional engagement elements can be maintained in the engaged state. Thus, a task as described above does not occur. However, if the electrically driven pump is equipped, a cost increase and a weight increase cannot be avoided. Therefore, there is a demand that, without equipment of the electrically driven pimp, while the shock during the engagements of the frictional engagement elements at the time of the re-start of the engine after the automatic stop of the engine is reduced, a startability (a start performance) when the accelerator pedal is depressed is secured.
One of objects of the present invention is created in view of the task as described above. On a vehicular control apparatus in which an automatic transmission is equipped, the cost is reduced and a compatibility between a security of the startability and a suppression of the shock is established. It should be noted that, not only limited to this object, an action and an effect introduced according to each structure described as shown in the embodiment to carry out the invention which will be described later and which cannot be obtained from the conventional art can be achieved and can be positioned as another object of the present invention.